Test results on 3 GHz structures for a superconducting linear collider

It was shown that the improvement on the performance of single cell Nb cavities made during the last 5 years by advanced dustfree mounting and firing techniques can be successfully transferred to multicell structures. Acceleration gradients of 22 MV/m in the best 5-cell and 16 MV/m in the first 9-cell cavity of improved cell shape have been achieved. The increase of E/sub acc/ beyond 25 MV/m needs additional investigation on single cell cavities. Nevertheless, superconducting accelerators are a promising option for building a linear collider for electrons with beam energies in excess of 300 GeV. >